File size bigger when using "tuning" setting

[Isley]

Hello.

I started ripping some of my blu-ray recently for easier access and been fiddling with settings to get a good compromise between file size and quality.

I settled for 720p and DXVA output (since I'll be playing them from my PC), and a crf of 21, which gives me a great quality.

The last setting I fiddled with was 'tuning', and I found the result quite strange. Since this is blu-ray is a live-action TV show (toughly 40 min per episode) I went for the Movie option and I didn't observe and change in quality whatsoever. The size of the file however was not the same.

Movie tuning on : 1.05 GB
No tuning : 862 MB

Did I chose a CRF too low for tuning to be relevant and if yes, what are tunings good for if their result can be achieved by simply lowering the CRF ?

[Blue_MiSfit]

CRF will produce different results with different settings.

Compare the two. Do you see a visual difference? If no, skip the tuning and you're done.

If you do see a difference, can you accept the increased bitrate? If yes, keep the tuning and you're done.

If you want the file size to be smaller, increase crf and re-encode. If you like the result keep it. Otherwise you can keep your original encode

[Asmodian]

I recommend finding the CRF value you like after you pick a tuning. x264's tunings a pretty good in my experiance, they usually let you use a smaller file for the same apparent quality. If 21 is already transparent, with tune film or without, then a higher CRF will likely also be transparent with tune film. It can be a decimal value too, like 21.5. Even 0.1 CRF can have a pretty big impact on the final size, and +0.01 will make it a little smaller without changing the quality at all, at least that you can notice.

Of course the content type matters a lot and different movies will vary wildly in how they behave with any particular set of options.